Signal clearing relay for centralized traffic control systems of the code type



1951 J. l. GRAMMER SIGNAL CLEARING RELAY FOR CENTRALIZED TRAFFIC CONTROLSYSTEM OF THE CODE TYPE Filed Feb.

MNNNN IN VENTOR James I 69 01220290 d r V @QRN Hi5 ATTORNEY PatentedNov. 20, 1951 SIGNAL CLEARING RELAY FOR CENTRAL- IZED TRAFFIC CONTROLSYSTEMS OF THE CODE TYPE James I. Grammar, Western Springs, 111.,assignor to Westinghouse Air Brake Company, a corporation ofPennsylvania Application February 19, 1946, Serial No. 648,716

3 Claims. (01. 246-4) My invention relates to centralized trafliccontrol systems for railroads, and to improved apparatus for the remotecontrol of railway signals or the like, by a selective communicationsystem of the code type, such for example, as that shown in LettersPatent of the United States, No. 2,229,249, issued January 21, 1941, toLloyd V. Lewis, for Remote Control Systems.

In remote control systems of this type, the

components are assembled in the form of indi-- vidual storage units witheach identified by a selective code call and adapted to control andindicate a related group of traflic governing devices, such as atrackswitch, and the railway signals which govern trafiic movements overthe switch. Each unit is linked, by means of its code call, with acorresponding storage unit located in the oflice control machine whichgoverns the transmission of a code includingits code call followed by aseries of code elements for controlling the switches and signals inaccordance with the positions of their control levers, when set intooperation by pressinga code starting button to select the code call.Each oflice storage ,unit also includes a group of indication stickrelays which respond to the elements of indication codes transmittedfrom the associated station unit to indicate the condition of the switchand signals and for also indicating the condition of one or more tracksections.

The present invention relates more particularly to the control ofrailway signals by systems of this character, and provides novel andimproved means for preventing a change in the character of a codeelement for controlling a signal to its clear or stop position, exceptby the combined operation of the signal lever and of a code start ingbutton associated with but independent of the lever, or upon thereception of a code indicating that a train has accepted a signal andhas caused it to be put to stop.

Briefly described, my invention is embodied in a signal clearingrelayfor electrically interlocking each signal lever with the associated codestarting button, and with a code-controlled indication relay of thesystem which is operated whenever the corresponding signal is put tostop by a passing train. The contacts of the signal clearing relayreplace the usual lever contacts in the circuits for effecting the codecontrol of the signal, and this relay is arranged to be picked up, whenthe signal lever has been placed in its reverse or signal clearingposition, only by operating the associated code starting button and thenonly if the indication relay referred to reflects the proper track 2conditions. The signal clearing relay maybe released by the operator to'effect the manual control of the signal to stop, only by operating thestarting button after he: has restored the signal to its normalposition. This relay is released automatically, by the operation of theindication relay referred to,

when the signal is putto stop by a passing train.. Applicants signallever and code starting button, are thus interlocked so as torequiretheir combined operation to change .the. character of a signalcontrolling code element, without any mechanical connectiomwith theadvantage that the operator is enabled to operate thelever between itsnormal andureverse positions without causing the transmission of acontrol code whens ever this is desirable.

One object of myinvention is to, facilitate the, control of unrelateddevicesloy the same storage unit, so that a code. containing anelementassigned to the control of asignal or the like may also includeelements for. controlling other devices having starting buttons foractuating, the same storage unit, and when codes are initiated by theoperation of starting buttons associated with such other devices, theelement which controls the signal will retain the same character asoriginally established, even though the position of the sig nal lever,has inadvertently changed, solong as, the starting button directlyassociated with the signal lever is notoperated. My invention, isparticularly advantageous in connection with the controlof two or moreunassociated signals by the same storage unit, and also in connectionwith the control of single track signaling systems of the reversibletype, in which the operation of the starting button for the signal ateither end of a blockis effective, at times to cause the transmission ofcodes to both ends of the block order to reversethe: direction oftrafiic move-r ment, as shown, for example, in. an application forLetters Patent ofthe United States, Serial No. 501,254, filed September4, 1943; by Henry S. Young, for Railway Tramc Controlling-Apparatus, nowPatentNo."2 ,420,579, issued May 13, 1947.

My invention is an improvement on that shown and claimed in applicationfor Letters Patent of the United States, Serial No. 649,598, of ArthurL1" Jerome, Lloyd V. Lewis and Frank T. Pascoe, filed February 23, 1946.I I

Other objects and features of my invention will be pointedout as thedescription proceeds,

shalll lnow describe one or! .91 anarchist as'iaoio trollable by theirrespective signal levers 28G and;

4SG. In such cases it is preferable to mount the levers in separatepanels orsrictionsv of the opera: ators control board to more readilyidentify the levers with the signals on the track diagram mounted abovethe levers. p

It is to be understood that the signals arecontrolled and indicated by acode type communication system such as that shown and described thehereinbefore mentioned Lewis patent, em-

ploying but one ofilce storage unit and one staknown and a detailedexplanation thereof is not needed for. an understanding of my invention,and the portions thereof relating directly to my invention areillustrated herein in a simplified diagrammatic form. .To furthersimplify the circuits, only the terminals. of the local sources. ofcurrent for energizing the. relays are shown, thesebeing identified bythe. reference characters B and C, respectively...

Each. signal lever 28G. or 4SGhas a starting button ZS'IB. or 4STB,which is effective when operated to. energize the ofi'ice. startingrelay. ST over contact a of thebuttonto initiate the transmission of acode containing adistinctive code call: by which a selector relay OS at.the office and a delivery relay D are operated to link the oificeunitwith the corresponding station unit. Each signal lever has a signalclearing relay ZRGS. or ILGS associatedtherewith in accordance with myinvention. Each relay- ZRGS or 4LG S picks up. over the lever contactoand the normally 'openstartingbutton contact 12' when the associatedstarting button 2S'I-B or 'GSTB is operated, provided the controllingsignal'lever is then in'its reversed or'signal clearing position, and isheld-energized afterthe button is released by a stick circuitincludingits contact a and the normallyclosed contact b ofthe button afterthelatter is released, regardless oftheLlevenposi--' tion.- Each-relay-2RGSor lLGS may be released manually by pressing the associated startingbutton when the lever is inits normal position, as shown, and isalsoreleased automaticallywhen a codeis received indicating that a trainhasaccepted the signal and put it to stop byenter-ing the controllingtrack section IT or 3T.

When a control code is transmitted, a series of control channels ismomentarilyestablished, ot whichbut threeare shown, designated. I, 3.and 4. and; represented simply as. dir'ectwire connections asmay also.beused when. the;:,s ignal s ;are u a'sbort: d stance fr m. hefiqcerherebr. he;

mai taine s; a l la US. ar f p tat d 01 the signals 2R and lL, as shown;

The delivery relay D also has a contact {for energizing the stationstartingrelay STto initiate control; relays -2RI-I S and 4LHS and a 4the transmission of a return indication code following the reception ofeach control code. In the code initiated by relay ST, a start releaserelay V0 is operated to release relay ST, also a conv nector relay MSPat the station and a delivery relay OD at theeffice are operated toestablish four indication channels, 51 to .12, whereby the trackindication relays ITK and 3TB: are picked .up, if the track sections ITand 3T are occupied,

to light red lamps ITKE and 3TKE on the track diagram, and torelease'relay ZRGS or lLGS, if

' energized. If signaliR or 4L is at clear, a signal indication relayZRI-IK or ALHK is picked up over channel It). orl2, respectively, tolight a green nui anc s 4LE-mcunted above the corresponding lever;and'to'extinguish the redlamp ZNE 102541.51 a sqcietes t er Channel 9 iscontrolled by the track storage relay 'BTS, which is energized over backcontact 0 of the track relay ITR, and serves to prevent the loss of atrack occupied indication in the event its transmission is delayed untilthe section is vacated. Relay HTS is provided with a stick circuitcontrolled by a valve relay 9V associated therewith, which functionslike the similarly designated relay'of the Lewis patent, and it is to beunderstood that relay 9V: picks up when a track occupied code is fullytransmitted over the correspondingchannel, and releases when a trackclear code is fully transmitted over that channel. Contacts 0 of relays9V and 9T5 pro-J v-ide' circuits for energizing relay ST to initiate thetransmission of a code in response to a change in the position of relay9T8.

It will be seen that if the track relay I'IR, releases to pickup'relay9T8, relay ST will pick up over front contact 0- of relay STS toinitiate the trar ismission of a code in which channel a 9 is energizedover back contact 0 of 1 the track relay I'TR to indicate the occupancyof section IT. Ifit happens that relay ITR picks up before the trackoccupied code is transmitted, terminal B at back contact a of relay. 9Vwill hold relay HTS energizedand will apply energy to channel 9'untilthe track occupied code bywhich relay 9V picked up is transmitted.

Channel l I is similarly controlledby real 3TB, but this channel is alsoemployed to transmitan additional indication controlled by a poweroilrelay POR for which it-maybe assumed thata separate channelisunavailable. I

It is to be understood that the source of current at the station havingthe terminals B and I C is a battery which is normally maintainedcharged bya primary source of power having the lay PORA to transmits,code to pick up relay MK and to thereby light lamp- 3TKE: If lamp SIKE'becomes lighted when signal 4L has not been'cleared, or if it becomeslightedw-hen the signal has been cleared and-'lamp- 4LE remains lighted,the operator reverses the maintainers call key MC, and transmits a codeto pick uprelay US,'which lights lampE and. disconnects terminal B fromback contact b 'of relay POR to cancel the indication displayed by lampS'IKE. The power-Jottindication thus distinguishable from thetrackoccupied indication transmitted over the same channel, due totrackoccupancy or track circuit failure, by the fact that the operatoris enabledto cancel. it at will; i

I shall now assume that the apparatus is inits normal condition, andthat the operator reverses lever 2SG and presses button ,2STB, therebyenergizing relays ZRGS and 0ST and initiating a control code bywhichrelay, 2RHS is energized over channel I, this channel beingsupplied with energy over contact 0 of relay 2RGS. Mechanism 2RG becomesenergized over contact "c of relay ZRHS and contacta of relay ITR tocause signal 2R to indicate clear, and ,the closing of contact a ofrelay D when. the controlcode is received energizes relay,, ST toinitiate areturn indication code by which relayfzPtHK is energized tolight lamp ZRE and extinguish lamp ZNE, .re-,

lay ITK remaining released. A

Other control codes may now-be transmitted by the same unit, to clear.signal 4L,or operate relay US, in each of which the energy appliedtochannel I by contact 0 of relayZRGS maintains relay ZRI-IS energizedas'required, even though lever ZSG is inadvertently moved to open itscontact a.

I shall now assume that. a trainlenters sec-. tion IT, releasing relayITR. to restore signal ZRG to stop and energizing relays QTSyand ST tostore an indication code for transmission, but

that the transmission of: this code is delayed, due. perhaps to thetransmission of indication codes.

contact b of relay I'I'R andis maintained released by the opening ofback contact d of relay STS.

It follows that relay. ZRHS will not respond to, a signal clearing codeas long as relay ,BTS is,

picked up even though section IT hasbeen vacated, and. signal 2RWillhnot be cleared by a code received prior to the transmission of thetrack occupied indication.

When the code storedby relay ST is being transmitted, relay STS is inits picked up position and mechanism ZRG is released, so that this codeenergizes relay I'IK to light lamp I IKE and to release relay 2RGS, andalsoreleases relay ZR-HK to light lamp 2NE' and extinguish lamp ZRE, andat the end of this code relay 9V picks up to open the circuit for relayST extending to terminalB at front contact 0 of relay'9TS and also opensthe stick circuit for relay STS, but'if section IT is stilloccupiedrelay STS is heldsenergized by relay ITR, and holds relay 2RHSreleased. If section IT has been vacated, relay 9T8 is released by relay9V, completing a new circuit for relay ST over back contact 0 of relayHTS and front contact 0 of relay 9V, to initiate the transmission of anindication code to release relay ITK and extinguish lamp ITKE. Relay 9Vis released by this code to open the circuit over which relay ST wasenergized. Back contact d of relay QTS is now closed, rendering relayZRHS responsive to control codes in which energy is applied to channeli, but relay 2RGS has been released by the preceding indication code andchannel I is now open. Consequently relay ZRHS will not become energizedto reclear signal 2R, by control codes which include an element assignedto the control of relay ZRHS, even though 6 lever 28G is moved to apositionto close its contact a, unless button ZSTB is also operated topick up relay 2RGS.

Following a temporary interruption of the have been put to stop by atrain'before the sys-' tem is restored, but in any case, thetransmission of a control code for clearing it, by opera tion of button2STB with lever ZSG reversed, after the system is restored, will notchange. its

condition. That is to say, if signal 2R is still at clear the code willmaintain it clear, and if it has been put to stop by a train the circuitfor relay ZRHS is held open by relay BTS, dueto the fact that anindication of the occupancy of section IT has not been transmitted,rendering the code ineffective to reclear the signal.

The signal clearing relay ZRGS is also of ultility wholly apart from thecontrol by the track storage relay 9TS. In the control of single tracksignaling, for example, it is a common practice for an operator toreverse the lever for the entering and leaving signals for a block andto then press the starting button for the entering signal only, delayingthe clearing of the leaving signal until he has determined whether ornot the train should enter a siding at the location of the leavingsignal. In certain systems, the operation, of

the entering end starting button is arranged. to,

cause the transmission of codes to both ends of the block, as alreadymentioned, one of which, would cause the leaving signal to clear under,

the conditions mentioned, in the absence of a signal clearing relay suchas relay 2RGS for that In the system referred to, and; in fact,

signal. in signaling systems generally, the clearing of a signalcontrolling movements over a track switch renders time looking effectiveto prevent the operation of the switch. It follows that the inadvertentclearing of the leaving signal under the condition mentioned would delaythe movement of the train into the siding, if this were required.

Although in the foregoin I have described my invention principally withreference to signal 2R, it is to be understood that the circuits forsignal 4L are similar, except as modified to provide for indicating thepower-off conditions by lamp 3TKE. These modifications include a frontcontact b of the signal indication relay 4LHK bridging contact b ofrelay 3TK, in the circuit for relay 4LGS, in order to prevent itsrelease when relay 3TK is picked up by the release of relay POR. Theenergization of relay lLHK along with relay 3TK obviously indicates thatthe track relay 3TB, has not been released. Back contact 0 of the trackrelay 3TB. controls a pickup circuit for relay HTS in which a repeatingrelay 3TX is interposed, so that relays fiTX and I ITS pick up incascade in response to the release of relay 3TB. Relay HTS is heldenergized by relay NV and relay 3TX is held energized over a stickcircuit controlled by relay HTS. The reason for this arrangement is thata back contact of relay HTS, corresponding to contact d of relay 9T8 in.the circuit for relay 2RHS; can;- not. properly be. included in thecircuit for relay 2LHS, to prevent its energization by'a control codereceivedafter. section 3T is: vacated but prior to the transmission ofan indication code by which relay HTS is released, since this mightcausesignal 2L to be put to stop'improperly, as a re. sult, oftheoperation of relay POR. Accordingly, the' repeating relay .3'IX isprovided, having a. back contact. b. in the circuit for relay ZLHS inplace of a. contact. of relay 1 ITS. Relay 3TX, serves. to hold thecircuit for relay lLI-IS open whenrelay I. ITS is. picked up by therelease of relay 3312B, :but not when relay HTS is picked upbyptherelease of relay PQR as. will be readily apparent irom.thedrawing;

-Although. I. have; herein shown only one form ofrapparatus. embcdyingmyinvention and one modification thereof, it will be understood thatvarious. modifications. may be madeltherein within.

the scope of the appended claims without departing-from the spirit andscope of myinventiom Having thus described my invention, what I by: saidbutton, and a stick circuit for the stick relay including said signallever contactbridged:

by. a normally closed contact controlled by said' button.

2." In acentralized traffic control system havinga communication systemconnecting anoillce and a station, a railway signal for controllingtrafiic movements over a detector track section, a track relay for saidsection, a signal control relay controlled over a front contact-of saidtrack relay, a secondcontrol relay and a locally controllednormallyenergized relay, all located atsaid station; a track indication relaywhichis energized by saidcommunication systemywhen the track'relay-isreleased and alsowhen both said second control relay and said normallyenergized relay are released, a signal indication relay controlled bysaid communication system which reflects the-condition of'said signal:control-relay, a signallever for governing the signal control relay, asecond lever for governing the second control relay, and a stickrelayall located at: said ofiice, pick-up and stick'circuits for'ef' acommunicationv system. for

8 iectl ng-the-energization or: release of" said stick: relay inaccordance with the position. to which said signal lever is operated,said circuits includ-' ing a back contact of said. track indicationrelaybridged by a: contact closed by said signal indication relay if the;signal control relay is energized; means governed by said communicationsystem for energizing said signal control relay when said stick relayisenergizedand. for controlling said second control relay in accordancewith the positionof saidjsecond. lever, and means associated with saidlevers forvisually indicating the positions of 'saidindication relays.

3'. In acentralized traflic control system, a detector trackv sectionhaving a track relay, a:

signal for governing trafiic. movements over said section, a controlrelay for-the signal having a normal and a signal clearing position, acode type communicationsystem for governing said control relay from acontrol cities and for-indicating the condition of occupancy of saiddetector track section at said ofiice; a control-lever, a stick relayand a starting button for causing the transmission of control codes bysaid communication system, all located at saidoflice, a. storage relayatv the station controlled by said. track relay for causingindications'of the occu pied or unoccupied condition of said detector section to theoffice and for storing each occupied indication until such indication istransmitted, pick-u-p-and stick circuits: for said stick. relayincluding a contact closedonly when said .unoccupied conditionisindicated, said pick-up circuit including a reverse contact of saidlever anda. normally open contact of said button, said stick circuitincluding said lever contact bridged. by a normally closed contact ofsaid button, means for operating said control relay to its. signalclearing position in response to a control code transmitted when saidstick relay is. energ-ized provided said storage relay has not been.operated to store an indication. code. for transe mission, and means foroperating said control:

relay to its normal position in response to a control code transmittedwhen said stick relay is released. 7 JAMES I; GRAMMER.

7 REFERENCES CITED The following referencesare; of record in the fileof: thispatent:

UNITED STATES PATENTS Number. Name Date 2,292,245. Snaveleyet al. Aug.4, 1942. 2,422,127 Pascoeet' al .June 10, 1947- Z,48@i,7.16: Lewis. Oct.I1, 1949 2,528,073 Pascoeet al. Oc,t. 31,. 1950-

